Carbon nanotubes field emission integrated triode amplifier array

Because the high frequency operation of a field emission triode amplifier is dictated by the cutoff frequency and not the electron transit time, a high ratio of transconductance, g(m) to the overlapping interelectrode capacitance, C-g is the desired outcome. Consequently, to achieve high frequency performance of the CNT amplifier array in this study, C-g was reduced by performing a dual-mask photolithography process to minimize the overlapping gate area, and, the insulating layer's thickness was increased. Moreover, wedge-shaped CNT emitter arrays are employed to increase emission sites, resulting in return higher g(m). Both dc and ac performance of the amplifier were characterized. The triode amplifier array exhibited a high current of similar to 0.32 mA (74 mA/cm(2)), g(m) of similar to 63 mu S and voltage gain of similar to 18 dB. Frequency response of the triode amplifier up to 20 kHz was also investigated. A theoretical cutoff frequency of > 70 MHz could be achieved with proper shielding of the test setup. (c) 2006 Published by Elsevier B.V.